Texas Instruments PLUS TI-89 - Manual (Page 530)

Appendix A: Functions and Instructions 513
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 513 of 132
tExpand() MATH\Algebra\Trig menu
tExpand( expression1 ) ⇒ expression
Returns an expression in which sines and
cosines of integer-multiple angles, angle
sums, and angle differences are expanded.
Because of the identity (sin(x))
2 +(cos(x)) 2 =1,
there are many possible equivalent results.
Consequently, a result might differ from a
result shown in other publications.
Sometimes tExpand() will accomplish your
goals when the default trigonometric
simplification does not.
tExpand() tends to
reverse transformations done by tCollect() .
Sometimes applying tCollect() to a result from
tExpand() , or vice versa, in two separate steps
simplifies an expression.
Note: Degree-mode scaling by p/180
interferes with the ability of tExpand() to
recognize expandable forms. For best results,
tExpand() should be used in Radian mode.
tExpand(sin(3 f)) ¸
4ø sin( f)ø (cos(f))с м sin(f)
tExpand(cos( aì b)) ¸
cos( a)ø cos(b)+sin(a)ø sin(b)
Text CATALOG
Text promptString
Displays the character string promptString
dialog box.
If used as part of a Dialog...EndDlog block ,
promptString is displayed inside that dialog
box. If used as a standalone instruction, Text
creates a dialog box to display the string.
Text "Have a nice day." ¸
Done
Then See If, page 456.
Title CATALOG
Title titleString , [ Lbl ]
Creates the title of a pull-down menu or
dialog box when used inside a
Toolbar or
Custom construct, or a Dialog...EndDlog
block.
Note: Lbl is only valid in the Toolbar
construct. When present, it allows the menu
choice to branch to a specified label inside
the program.
Program segment:
©
:Dialog
:Title
"This is a dialog
box"
:Request
"Your name",Str1
:Dropdown "Month you were
born",
seq(string(i),i,1,12),Var1
:EndDlog
©